Ethephon: a tool to boost gum arabic production from Acacia senegal and to enhance gummosis processes

Abstract

Gum arabic production from Acacia senegal is lower in sub-humid areas than arid areas. Water stress is thought to be the reason for higher yields in arid areas. The application of ethephon is thought to mimic the effect of water stress in other plants. The objective of this study was to determine if the application of ethephon would increase the gum yields of Acacia senegal under sub-humid conditions in Cameroon. Trees receiving 40 or 120 mg ethephon were compared to controls in field experiments at a semi-arid and a sub-humid location in Northern Cameroon, over two seasons. Two provenances from drier areas (Sudan) were compared to the local one. In the first season, gum yield of the local provenance treated with ethephon was increased by 400-600 % compared to the untreated trees. Gum yield at the semi-arid location was 77, 313 and 214 g/tree with 0, 40 and 120 mg ethephon/tree, respectively, while at the sub-humid location, it was 30, 186 and 114 g/tree with 0, 40 and 120 mg ethephon/tree. However, in the second season, the effect of ethephon was not significant in the semi-arid area, whereas it was evident in the sub-humid area (up to 478 g/tree). Moreover, ethephon did not affect gum yield of provenances from drier areas (Sudan). This showed that the water-stress hypothesis has to be refined. The development of ethephon-based tapping systems is promising, but requires further studies with a wider range of environmental conditions and A. senegal provenances.

Ethephon-induced gum Arabic exudation technique and its sustainability in arid and semi-arid regions of India

“…Gum yield was significantly ( p ¼ 0.034346) enhanced by increasing the concentration of Ethephon. These results are in line with the findings by Bhatt and Ram Mohan (1990) in India who also reported increased gum yield with increased Ethephon concentration up to 960 mg/tree, but contradict results from a recent study in northern Cameroon by Abib et al (2013) who reported low yield with higher concentration (120 mg/tree) of Ethephon and high yield under lower concentration (40 mg/tree) of Ethephon. Further investigations are needed to find out the reasons for this discrepancy that whether it is due to other factors (climate, application technique, tree provenance?).…”

“…This method, in which Ethephon is directly injected into the tree, quickly reaches the tissues involved in gum production. We consider this method to be better adapted than other methods such as brushing Ethephon after bark removal (Abib et al 2013), in which chances of loss of most of the applied Ethephon through evaporation cannot be avoided.…”

“…Leguminosae)" (FAO 1999). A. senegal is the most important source of gum arabic (Abib et al 2013). It exudates gum during the hot dry season when the tree is under extreme dehydration stress conditions and its leaves have completely fallen.…”

Sandy soil fertility restoration and crops yields after conversion of long term Acacia senegal planted fallows in North Cameroon

“…Improved tree fallow is one of the possible approaches (Muthuri et al, 2005;Kissi, 2011). In semiarid sub-Saharan, planting A. senegal seemed to be more adapted because of its high adaptation potential to drought and fodder generation for animal as well as wood and gum arabic (Nasreldin, 2004;Palou Madi et al, 2010;Abib et al, 2013). It can also stabilize sandy soils and restore their fertility, protecting them from erosion (Mallet et al, 2002;Harmand et al, 2012).…”

“…Unlike in many countries, an integration of this tree in Cameroon agroforestry systems was neither significant nor documented. Former studies always focused on improving gum arabic production or commercialization (Mallet et al, 2002;Palou Madi et al, 2010;Harmand et al, 2012;Mujawamariya et al, 2013;Abib et al, 2013). Little works had concerned soil fertility restoration at the lowest possible cost through their integration in agroforestry systems (Abib et al, 2013;Mujawamariya et al, 2013).…”